Goss' Wilt, caused by the bacterial pathogen Clavibacter michiganensis subsp. nebraskensis (CN), is a disease that causes significant damage to corn crops. Goss' Wilt has been identified throughout the U.S. Corn Belt, primarily in the western regions. Symptoms include leaf freckles which are small dark green to black water soaked spots and vascular wilt which results in loss of yield. Conservation tillage practices can increase pervasiveness because the bacterial pathogen Clavibacter michiganensis subsp. nebraskensis (CN) can overwinter in debris, particularly stalks, from infected corn plants (Bradbury, J. F. IMI description of Fungi and Bacteria, (1998)). A mapping study conducted by Rocheford et al., reported a genomic region on maize Chromosome 4 associated with Goss' Wilt (Rocheford, et al., Journal of Heredity 80(5), (1989)). Goss' Wilt is a significant pathogen of corn, and a need exists for development of disease resistant lines.
Breeding for corn plants resistant to Goss' Wilt can be greatly facilitated by the use of marker-assisted selection. Of the classes of genetic markers, single nucleotide polymorphisms (SNPs) have characteristics which make them preferential to other genetic markers in detecting, selecting for, and introgressing disease resistance in a corn plant. SNPs are preferred because technologies are available for automated, high-throughput screening of SNP markers, which can decrease the time to select for and introgress disease resistance in corn plants. Further, SNP markers are ideal because the likelihood that a particular SNP allele is derived from independent origins in the extant population of a particular species is very low. As such, SNP markers are useful for tracking and assisting introgression of disease resistance alleles, particularly in the case of disease resistance haplotypes.
The present invention further provides and includes a method for screening and selecting a corn plant comprising QTL for Goss' Wilt resistance using endemic strains of CN and SNP marker technology.